Insert-jaws for lathe-chucks.



J. E. GBARHART.

INSERT JAWS FOR LATHE GHUCKS.

urmonron FILED 1119.30. 1911.

1,013,289. Patented Jan. 2, 1912.

JE Gearhari,

Q. 73. 7741M. mMfiMM 6 Home 1 JOSEPH E. GEARHART, OF CLEARFIELD, PENNSYLVANIA.

INSERT-JAWS FOR LATHE-CHUCKS.

Specification of Letters Patent.

Patented Jan. 2, 1912.

Application filed August 30, 1911. Serial No. 646,821).

To all whom it may concern:

Be it known that I, JOSEPH E. GEARHART, a citizen of the United States, residing at Olearfield, in the county of Clearfield and State of Pennsylvania, have invented certain new and useful Improvements in In sert-Jaws for Lathe-Chucks, of which the following is a specification, reference being had to the accompanying drawings.

This invention relates to insert jaws for use in connection with the usual lathe chuck.

It is a well known fact that the radially arranged jaws in the usual lathe chuck have sliding movement for gripping the work of certain dimensions, for instanqe, some jaws have movement only sufficient to clamp work one-half inch in diameter.

Therefore, the invention has for its object to provide an insert or supplemental jaw whereby work may be operated upon which may be slightly less than one-eighth of an inch in diameter.

With the above and other objects in view, the invention resides in the novel features of construction, combination and arrangement of parts as will be more fully hereinafter described, claimed, and illustrated in the accompanying drawings, in which,

Figure l is a front elevation of a lathe chuck, the device being shown in place; Fig. 2 is a longitudinal sectional View through the device; Fig. 3 is a transverse sectional view of the same; Fig. 4 is a detail perspective view of one of the supplemental jaws.

Referring to the drawings, the numeral 1 designates a lathe chuck having adjustably mounted thereon radially arranged jaws 2, and between the opposing ends of which the device is to be operated.

The device consists of an inner rectangular plate 3 and an outer rectangular plate 4, the latter plate being slightly greater in diameter than the inner jlolate 3. The outer plate 1 is provided wit a series of spaced slots 5, and the inner plate is provided with similar slots 6. Adapted for sliding movement between the inner and outer plates 3 and 4 are a series of jaws 7, said jaws being substantially triangular in cross section, and are provided with serrated gripping faces 8. The jaws 7 are each provided upon one of their ends with rectangular heads 9, each of which is provided with an internally .threaded bore 10. The other ends of the jaws 7 are each provided with a similar bore 11 into whichscrews 12 are inserted after formed rectangular, undue rocking of the jaws is prevented. Formed in the central portion of the gripping faces 8 are transverse grooves 13. Adapted to seat in the grooves 13 is a band spring 14, the ends of which are arranged in overlapping relation, so that the same may freely contract when pressure is applied to the jaws? and expand and force said jaws away from each other when pressure is relieved.

When the device is in place, the opposing ends of the radially arranged jaws of the chuck 1 rest upon the outer faces of the jaws 7, and, upon movement being imparted to the jaws 2, the jaws 7 will be forced inwardly and against the tension of the spring 14 to grip the work. When it is desired to remove the work, the jaws 2 of the chuck are operated and, upon operation, the spring 14 will tend to force the jaws 7 away from each other to permit the ready removal of the work. h

Having thus described my invention, what I claim as new and desire to secure by Letters-Patent is:

1. In combination with a chuck provided with a series of radially arranged jaws, an insert consisting of inner and outer plates. supplemental jaws slidably mounted between said plates whereby, when the radially arranged jaws of the chuck are operated, the supplemental jaws will be forced toward each other to grip the work, and means for sliding the supplemental jaws outwardly.

2. In combination with a chuck provided with a series of radially arranged jaws, an insert consisting of inner and outer plates, each of which is provided With a series of alined slots, supplemental jaws slidably mounted in said slots, said jaws having gripping faces, transverse grooves formed in the gripping faces, a band spring seated in said grooves and being adapted to contract when pressure is applied to the supplemental jaws and't-o expand when the pressure is relieved upon the supplemental aws whereby said jaws are forced away from each other.

3. In combination with a lathe chuck provided with a series of radially arranged said spring being adapted to expand to jaws, an insert comprising a pair of lates, cause the supplemental jaws to move away said plates being provided with alined slots, from each other when the radially arranged 15 supplemental jaws arranged between said jaws of the chuck are operated in an oppo- 5 plates, one of the ends of the jaws being site direction.

provided with a rectangular head for en- In testimony whereof I hereunto aflix my gagement with the slots of one of the plates, signature in the presence of two witnesses.

transverse grooves formed in the gripping face of the supplemental jaws, a band spring JOSEPH GEARHART 1o seated in said grooves and adapted to con- Witnesses: C

tract upon operation of the jaws of the GUssIE OURLEY, chuck in one direction to clamp the work, W. I. Swoorn.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of latentl, s Washington, D. 0." 

